Diesel fuel compositions



United States Patent 2,857,253 DIESEL FUEL COMPOSITIONS James B. Hinkamp, Birmingham, and Roy Sugimoto, Royal Oak, Mich., assignors to Ethyl Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application May 28, 1956 Serial N0. 587,473

2 Claims. (CI. 44-62) This invention relates to synergistic mixtures and in particular to synergistic distillate diesel fuel blends possessing improved stability and compatibility characteristics.

This application is a continuation-in-part of parent application Serial No. 323,165, filed November 28, 1952,

now abandoned.

Alkyl nitrates such as amyl nitrate are used to improve the combustion characteristics of diesel fuel. This improvement is spoken of as increase in cetane number.

Use of such alkyl nitrates has been of definite benefit to.

providing synergistic compositions which consist of diesel fuel to which is added minor amounts of alkyl nitrate and rosin amine. In a preferred form of this invention we pro vide diesel fuel to which has been added amyl nitrate and a mixture of dehydroabietylamine, tetrahydroabietylamine, dihydroabietylamine and .dextropimarylamine. Such mixtures have been found to synergistically improve the stability and compatibility characteristics of distillate fuels of the diesel type. Most preferably we employ synergistic mixtures comprising diesel fuel containing 0.005 to about 1.0 percent by weight of rosin amine and from 0.05 to about percent by weight of alkyl nitrate. Thus, the ratio of alkyl nitrate to rosin amine-in our synergistic mixtures ranges from about 10 to 1 to about 200010 1.

The ammonoid derivates of rosin comprising one member of the synergistic mixtures of this invention are ammonoid derivatives of rosin wherein nitrogen is linked by covalent bonds to at least one carbon atom and usually hydrogen atoms as well. Thus, these ammonoid derivatives of rosin can 'be defined as amaterial selected from the class consisting of rosin amine and rosin amine derivatives. Rosin amine has beenjdefined as a primary amine reacting as a mild alkali. The term rosin amine is used herein to include broadly the primary amines derived from various rosins or rosin acids whereby the carboxyl of the rosin or rosin acid is converted into a -CH NH group. Rosin, or colophony, the resin remaining after distilling turpentine from'the exudation of various species of pine, is composed largely of abietic acidand abietic acid anhydride. Rosin amines included within this invention are gum and wood rosm amines,-

derived respectively from gum and wood rosin and containing chiefly abietylamine; dehydrogenated rosin amine derived from dehydrogenated rosin and containing chiefly dehydroabietylamine; hydrorosin amine derived from hydrogenated gum or wood rosin and containing chiefly dihydroand tetrahydroabietylamine; heat treated rosin amine derived from heat .treated rosin; polymerized rosin droabietylamine. The rosin amines may be prepared by,

ice

derived from the pure rosin acids, namely, abietylamine, dihydroabietylamine, dehydroabietylamine and tetrahyreacting ammonia with a natural rosin or a modified rosin to form the nitrile from the carboxyl group in the rosin.

and then hydrogenating the rosin nitrile or modified rosin: nitrile to form the amine. The reactions involved in preparation of the rosin amines'may be generally illns-I trated as follows:

NH. -2n,o 5 2n, T i RCOOH RCOONHAY 'YRCN v R.CH:N l in which R represents a rosin acid nucleus, such as the.

abeit-, dehydroabiet--, dihydroabiet-, or tetrahydroabietradical. Derivatives of rosin amine comprise reaction products formed by the interaction of rosin amine with substances containing acidic functions or with hetero-j cyclic compounds known in the art as epoxides, such as ethylene oxide, propylene oxide, and the like. Thus,

rosin amine derivatives include rosin amine acetate, -gly-, I colate, -stearate, -pentachlorophenate, -naphthenate, poly- Ammonoid derivatives of rosin arev currently available as articles of comethanol rosin amine, and the like.

merce.

The rosin amine preferred as the distillate fuel additive. of this invention is a mixture of dehydroabietylamine,. tetrahydroabietylamine, dihydroabietylamine, and dextro-g pimarylamine having the structural formulae CH3 on. Dehydronbietylamlne C H3 C H2NH| CH3 we CH CH Tetrahvdroabletylamine 0H; CHzNH:

' CH3 CH3 Dihydroabietylamine om CHQNHQ OHK I CH3 I Dextropiniarylamine Patented Oct. 21,- v 1958:

. 3 1 This mixture of rosin amines is commercially available under the trade name Rosin Amine D.

The alkyl nitrates of our synergistic mixtures include the various straight and branched open chain esters of the character obtained by the 'interactionof nitric acid with the corresponding straight and branched open chain aliphatic alcohol. It is to be understood that the term alkylnitrate is also generic to mixturesof alkyl nitrates comprising esters of differing numbers of carbon atoms as well as mixtures of isomers of a single ester, but containing varying proportions of the diverse positional isomers. The former is illustrated by a mixture of C4,C and C alkyl nitrates whereas the latter can be exemplified by a mixture comprising any number of the eight theoretically possible positional isomers of army] nitrate. As indicated previously, alkyl nitrates both singly and in admixture have been used in theprior art as octane improvers. Suitable nitrate esters include the nitrate esters derived from methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tertiary butyl, and other homologous alcohols including the various positional isomers of amyl, heptyl, octyl, nonyl, decyl, and like alcohols ormixtures thereof. Amyl nitrate is preferred because of its outstanding effect in cetane number.

The synergistic mixtures of this invention greatly effect the stability and compatibility of diesel fuel. These are, in factytwo closely related'problems in the utilization of distillate fuels including both heating oil and diesel fuel, which have been of considerable concern to petroleum refiners. Compatibility can be defined as that characteristic ofv distillate fuels. which allows them to be mutually blended in all proportions without producing a product having properties less suitable than either constituent alone. Incompatibility, therefore, results in the formation of sludge and other undesirable products. In contrast, stability can be defined as the characteristic of a fuel which allows it to remain unaffected by its environment and unchanged with time. Consequently, instability often results in the formation of soluble gum or in the formation of chemical residues commonly termed insoluble gum, sludge, residue, and the like.

We have found that our mixtures synergistically improve the stability and compatibility characteristics of diesel fuel. That is .to say, our synergistic mixtures improve these characteristics to an extent which is greater than the sum of the improvementsimparted by either ingredient when added separatelyto the diesel fuel.

The procedure used to determine the stability-compatibility characteristics of distillate fuel blends of the present invention consists, in general, of preparing a blend of fuels posesssing notorious incompatibility characteristics. This was accomplished by mixing together equal volumes of a commercially available straight-run fuel and a commercially available catalytically-cracked fuel. A portion of this blended fuel was stored under a constant temperature of 110 F. whereas additional portions of the fuel were treated with minor proportions of rosin amine prior to storage under identical conditions. Periodically, samples of these blends were removed and the sediment and other insolublematter was filtered through tared filter papers and the residue was washed with hexane and weighed. Whenever suflicient sediment adhering to the storagecontainers was noted, it was carefully removed and treated in a manner analogous to the filtered sediment. To demonstrate these stabilitycompatibility characteristics of the distillate fuel blends of the present invention reference is made to the following specific examples, wherein all parts and percentages are by weight.

EXAMPLE I A fuel composed of equal volumes of commercially available straight-run and catalytically-cracked fuels was prepared by intimately mixing gallons of each of the aforementioned components. To 615 parts of this untreated fuel was added 0.12 parts of rosin amine made up of a mixture of dehydroabietylamine, tetrahydroabietylamine, dihydroabietylamine and dextropimarylamine and the resulting blend was intimately mixed producing a homogeneous fuel composition containing 0.02 percent of rosin amine. Likewise, to 615 parts of the original fuel blend was added 0.31 parts of rosin amine and a homogeneous fuel composition containing 0.05 percent was produced by agitating the aforementioned components. The treated and untreated samples were then stored at a constant temperature of 110 F. for a period of one month. The samples were then allowed to stand at room temperature for two additional months after which time the samples were filtered through tared filter papers. The residue was washed with hexane and weighed. Since there was essentially no sediment adhering to the containers, no correction for this was necessary. It was found that theclear fuelcontained 46.1 milligrams of sediment per liter whereas the fuel containing 0.02 percent of rosin amine contained 21.4 milligrams of sediment per liter. The fuel containing 0.05 percent of rosin amine contained 4.7 milligrams of sediment per liter. Thus, the fuel containing 0.02 percent of rosin amine contained 53.6 percent less sediment than the corresponding untreated fuel. Likewise, the fuel containing 0.05 percent of rosin amine contained 89.8 percent less sediment than the untreated fuel. The treated fuels above were satisfactory for use as burner and diesel fuels by virtue ofthe decreased amounts of sediment. 1

EXAMPLE II The fuels described in Example I were stored for three months at a constant temperature of 110 F. At the end of this time samples were removed and treated as described in the preceding example. In addition, the sediment adhering to the containers was removed and treated in the same fashion as the filterable solids. The data are presented in Table I. t

Table I Cone, Sedi- Adhering Total Additive Wt. ment, Sedi- Sedi- Percent mgJl ment, ment, mg./l. mg./l.

EXAMPLE III An additional series ofsamplesprepared in accordance with the procedureof Example I was removed fromstorage at 110 F. fora period of five months.

, nique for determining the amount of sediment consisted essentially of drying filter. papers in an oven at C. and; subsequently. allowing these papers to reach equilibrium under. conditions of constant temperatureand hu-,

;resentative fuels treated with rosin amine, one of the ingredientsof our synergistic mixtures. To demonstrate the stability and compatibility properties possessed 1by The tech- 5. fuels cohta'ining the synergistic niiirtures ofthdinstafit invention, namely, distillate fuel containing miner prpor tions of alkyl nitrate and rosin amine, reference is'ffiade to the following examples wherein all parts and per- 'centages are by weight.

EXAMPLE IV To 615 parts of thefuel composition described in EX- ample I was added 1.85 parts of amyl nitrate and 0.12 parts of rosin amine. The aforementioned components were intimately mixed producing a homogeneous fuel composition containing 0.3 percent of amyl nitrate and 0.02 percent of rosin amine. fuel compositions of the present invention, that is, a fuel containing 0.3 percent'df ainyl nitrate and 0.05 percent of rosin amine was prepared by adding to 615 parts of the untreated fuel descfibed in Example I, 1.85 parts of amyl nitrate and 0.31 parts of rosin amine and agimine. the esaltii i ixt e- 'Tfiese 1-. 9 1PQs 9n were'stored together with a fuel containing 0.3 peFc'eh't of amyl nitrate at a constant-temperature of 110 F. for one month. At the end of this" time the fuels were removed and allowed to stand for'two additional months at room temperature. The procedure as described in Example I was then repeated and it was found that the fuel containing 0.03 percent of arriyl nitrate contained 86.7 milligrams of sediment per liter whereas the fuel containing 0.3 percent of amyl nitrate and 0.02 percent of rosin amine contained 19.9 milligrams per liter of sediment. The fuel containing 0.3 percent of amyl nitrate and 0.05 percent of rosin amiaej w as found to contain 8.3 milligrams of sediment per liter. Consequently, two

of the fuels of the present inventioii namely, those containing an alkyl nitrate and 0.02 and 0.05 percent of rosin amine contained respectively 77.0 percent and 90.4 percent less sediment than the corresponding fuel not treated in accordance with the present invention.

EXAMPLE v The procedure as described in Exampe IV was repeated with but one variable, that is, thefuelswere allowed to stand at a temperature of 110 F. for a period of three months prior to determining the amounts of filterable sediment and sediment adhering to the storage containers. The data are presented in Table II. All samples contained 0.3 percent of amyl nitrate.

Table 11' Adherln Sediment,

Sedi ment, mg./1

Additive rosin amine Thus, the fuels of the present invention containing minor proportions of an alkyl nitrate and 0.02 and 0.05 percent of rosin arn'in'e contained respectively 21.2 percent and 48.3 percent less total sediment than an untreated fuel composition.

' "EXAMPLE- VI The fuel compositions described EXam le IYwere stored at 110 F. for five months. The arnou ntof sedinient formed during this period was" determined war Likewise, another of the 0 nitrate aria" 0.5 percent ofrosin amine contained'32fl milligrams of sedimeiitper liter. Thus, the fuels treated in-"accordance with the'p'resent invention contained respectively 4535' percent and 65.9:percent less sediment than the untreated fuel.

It will be seen' from the above examples that theFmiX- tu'r es' of additives employed in* this invention possess" a definite synergism. Fdr' example, it is' noted frornt'Example IV that diesel fuel to which 053 percentamyl nitrate was added, afterstanding at Rte-mac rntinth follow/e11 by standing at'rodin temperaturefor two month was found to have a deposit accumulation aiiiounting to 86y7' rhg/l. whereas thesame fuel treated in the same way withoiit'the amyl nitrate present (Example I) had; a deposit accumulation of 46.1: mg. /1.-' It is clea that amylnitrate although enhancingthe cetane theinven'njdn hut-ehly bvercomes the uiistabiliz'iii'g' ejitct at a" yliiitrat blit actually con erts this to a stabiliiiifg eaeeta d in fact this "stabilizing effect is even greater thaa that'achievedhy use bf-ros'in'aiiiiii alone. l-The same typefjdffsyirergishi is directed by each" aha everysy 'rgi's tic miXtur'e" or this invention; rd i afidther tllus't atidh.Example IILshfow's that a dies whefistbred at 110 F. for five iii'oriths gav'e a'a accumulation of 69.3 mg./l. The same fuel when st ed with 0.3" ercenra hw nitrate for the same time under hesame eeriditionsfgave a deposit accuiniilation of 945 ".1 Again theani'y'l nitrate d 're'ased the stabilftyoff -Theanienie1'whehs red'wi'th 0.05 per" edit 0 e uifder identical conditions" gave'a deposit 5ccuri'fiilatloii of 18.0 mgJl. The cofiibifid enact of the tv'v'ci[tidtii'tives if no synergism were present were baa 'stahilii'atibii t'Sf 51.3 ihgL/l: contributed by the rosin (6913 inJ/l'. for the clear fuelniinus 18.0 ing/l; for the aiiiiii containing fuel) and 25.2 g.-/1. oaaibate& by theaifiyl nitrate 69.3 ing/1. for the near flier 94:5 trig/l. for the fuehcontaifiin'g the nitrate).- 'Tlie sum of the two stabiliz'ifrig effects if; additive w'tiiiltl nigE/l. contributed by the rosih amine and the neg Stabilization Of 25.2 Dig/l. cbhtiiblited by the alkyl nitrate The actual stabili2ation as, shown in'Erra nple VIis 37.1 rag/'1'; (693 mg./l.. for theclear fuel rniiiiis 32.2 mg. /l. for the fuel containing the synergistic friiiitiif) Thus; the area ofthe syaeigis'ae mixture is again more than the sum of the efiects 0f the two" separate eaia bhehts. p I

Similar synergistic action is demonstrated by theothe'r mixtures (if this ia've tiait. p v v Th arafa raa of the riigreai hts' or an; synergistic irfiiitiire depend upon th e' 'cli aracter a the fuel and ,e nature" of the airignono'd derivative of rosin employ The am oii'ri t of alkyl nitrat be added is contingent'u" the nature of the allgyl nitrateemploy-ed and thed operations. ,the rosin amine or its derivatives with such cracked I operations. accord with similar considerations.

fent invention will become apparent to those skilled in the art. We wish, particularly, to indicate that we can prepare fluids, that is, compositions for use in diesel fuels comprising an alkyl nitrate or a mixture of alkyl nitrates and an ammonoid derivative of rosin wherein the propor- -tions of the aforesaid ingredients are adjusted such that when blended in fuels for compression ignition engines amounts of the components within the ranges previously specified are obtained. Thus, we can provide a composition foruse in distillate fuel comprising parts by weight of alkyl nitrate to 1 part by weight of an am- .monoid derivative of rosin.

An illustrative example of such a composition can be prepared by combining 1000 pounds of amyl nitrate with 100 pounds of rosin amine .and shaking, stir-ring or otherwise agitating the resulting mixture to produce a homogeneous diesel fluid of our invention. An improved distillate fuel composition of the present invention can be provided by blending 11 parts of the fluid with 10,000 parts of distillate fuel.

Similarly, by blending 22 parts of the aforementioned fluid with 10,000 parts of distillate fuel we can provide an additional improved fuel composition of this invention. Likewise, we can provide other diesel fluids of this invention comprising up to about 2000 parts by weight of alkyl nitrate to 1 part by weight of ammonoid derivative of rosin. For example, we can combine and intimately mix 2000 or 2500 pounds of isooctyl nitrate with 100 pounds of rosin amine to prepare other unique and important fluids of our invention. In accordance with the preceding, we can prepare compositions for use in distillate fuel such as, for example, compositions comprising butyl nitrate and rosin amine, amyl nitrate and rosin amine naphthenate, amyl nitrate and rosin amine stearate, butyl stocks intended for blending purposes prior to blending such improved fuel with straight-run gas oil. A variation .of this within the contemplation of this invention is to blend the rosin amine or its derivatives with the straightrun gas oil prior to blending the resulting composition with cracked stocks. Likewise, the rosin amine or its {derivatives can be added during the blending of cracked and straight-run fuels or subsequent to such blending Blending of the alkyl nitrate is done in The rosin amine or its derivatives can be added prior to, concurrent with, or subsequent to the addition of the alkyl nitrate. Other variations include mixing the rosin .amine or its derivatives with the cracked stock and the alkyl nitrate with the straight-run distillate fuel prior to blending operations or adding a composition comprising alkyl nitrate and a material selected from the class con-- sisting of rosin amine and rosin amine derivatives to the 'catalytically cracked stocks prior to, concurrent with, or

subsequent to blending operations.

Having fully described the nature of the instant invention, the need therefor, and the best methods devised for carrying it out, we do not intend that our invention 1 We claim:

1. As anew composition of matter a diesel fuel consisting essentially of a hydrocarbonimixture boiling in the diesel fuel range and containing a synergistic mixture which consists of a lower alkyl nitrate and rosin amine wherein the rosin amine consists essentially of dehydroabietylamine having the structural formula on, CHaNH:

CH: 1 CH; CH! tetrahydroabietylamine having the structural formula CH1 CEzNHI CH3 CH3 dihydroabietylamine having the structural formula CHI CHINE:

CH; f H3 CH: and dextropimarylamine having the structural formula 0H; CHzNHn CH=CH3 H. CH3

the total amount of said lower alkyl nitrate being from 0.05 to 10 percent by weight of the fuel and the total amount of said rosin amine being 0.005 to 1.0 percent by weight of the fuel.

2. The composition of claim 1 wherein said lower alkyl nitrate is amyl nitrate,

References Cited in the file of this patent UNITED STATES PATENTS 2,456,569 Smith Dec. 14, 1948 2,484,010 Bried Oct. 11, 1949 2,684,292 Caron et a1. July 20, 1954 2,692,821 Ambrose et a1. Oct. 26, 1954 OTHER REFERENCES Soap and Sanitary Chemicals, December 1947, pages 147, 149, and 167. 

1. AS A NEW COMPOSITION OF MATTER A DIESEL FUEL CONSISTING ESSENTIASLLY OF A HYDROCARBON MIXTURE BOILING IN THE DIESEL FUEL RANGE AND CONTAINING A SYNERGISTIC MIXTURE WHICH CONSISTS OF A LOWER ALKYL NITRATE AND ROSIN AMINE WHEREIN THE ROSIN AMINE CONSISTS ESSENTIALLY OF DEHYDROABIETYLAMINE HAVING THE STRUCTURAL FORMULA 